Outstanding Copper Leaching Results and Scoping Study Commences
The performance of the copper leaching from column test-work on the Hollandaire deposit has been outstanding and the results include:
- Copper extraction of 91.9% on Column A in only 34 days
- Copper extraction of 91.7% on Column B in only 21 days
- Columns A and B net acid producing
- Scoping study commenced
This metallurgical column test-work has been undertaken to determine the viability of our unique copper leaching method, hence the optimal copper extraction method, and has leached copper into solution (refer to CYM ASX Announcement 27 November 2019).
Executive Director Barry Cahill commented "We are exceptionally pleased with the results received to date. Our expectation was that our unique leaching process would have the ability to both accelerate the leach time and produce excess acid on the Hollandaire material. The rapid leach time of the copper, using our unique leaching processes and parameters, has been astounding and outperformed our expectations.
The additional benefit of the leach reaction being acid producing is that it will generate surplus acid for use where the mineralised material is acid consuming, thus reducing the operating costs of the process.
The initial metallurgical results, in conjunction with recent drilling success, has given the Company the confidence to bring forward the commencement of a scoping study for the project. The study will focus on a heap leach operation designed to treat the Hollandaire copper deposits. The work to be undertaken will include a mineral resource update, further resource definition and extensional drilling, metallurgical test-work and commercial analysis on the potential for a rapid project start-up. A Project Manager has been appointed and has commenced work on the study."
Metallurgical Drill Holes
The metallurgical diamond drill programme (refer to CYM ASX announcement dated 14 October 2019) consisted of three holes for 320 metres into the mineralised envelope of the Hollandaire Prospect at the Cue Copper Project to provide representative samples for test-work to be undertaken as illustrated in Figure 1*.
The first hole in the metallurgical diamond drilling programme, 19HOMET001, was drilled into the Hollandaire West deposit and returned disseminated copper sulphide mineralisation. The second and third diamond drill holes in the programme, 19HOMET002 and 19HOMET003, targeted representative sections of the Hollandaire deposit and returned semi-massive to massive sulphide mineralisation. The results from the metallurgical diamond drill holes included:
- 10.4m @ 14.9% Cu in drill hole 19HOMET003 from 84.5m downhole including:
- 4.5m @ 21.9% Cu from 90.4m;
- 19.1m @ 1.3% Cu in drill hole 19HOMET002 from 85.9m downhole including:
- 6.4m @ 2.1% Cu from 98.6m;
- 27.9m @ 1.1% Cu in drill hole 19HOMET001 from 45.7m downhole including:
- 9.0m @ 1.6% Cu from 63.2m.
Hollandaire Metallurgical Test-Work Results
At the completion of drilling, core samples from the Cue Copper Project were received at the metallurgical laboratory in September 2019. The drill core was crushed, split and assayed for multi-element grades. Composites were then created for the Hollandaire deposit and the Hollandaire West deposit. Hollandaire samples were composited from holes 19HOMET002 and 19HOMET003 to create two column samples, Columns A and B, with copper grades of 5.10% and 5.24% respectively.
Diagnostic testing and mineralogical analysis were undertaken on the samples to determine the optimal parameters to use to undertake the column test-work.
The composites were then leached in separate columns with the resultant copper recovery over time under leach presented in Graph 1*.
Implications for the Project
The initial Hollandaire metallurgical test results have shorter leach time than expected. The effect of the very short leach times on a potential project is significant as it decreases the size of the heap leach pads, and consequently reduces the capital and operating cost requirements over the life of the operation.
Combined with the successful extensional resource drilling at Hollandaire (refer to CYM ASX Announcement 20 January 2020) has encouraged the Company that the critical mass of copper resource required for project development is close to being achieved.
Consequently, the Company has embarked upon a scoping study based on a heap leach operation designed to treat the Hollandaire copper deposits and to produce copper metal on-site. This study will utilise the knowledge the Company has gained over the previous 6 months to determine the optimal parameters required. A Project Manager for the study has been appointed and various consultants and suppliers have been contacted for input into various elements of the study.
Concurrently, planning has commenced for the next phase of drilling of the Hollandaire and Hollandaire West deposits, including the drilling of diamond core for further metallurgical testwork, as well as preparation for a mineral resource update. Future metallurgical test-work will focus on refining the operating parameters and reducing the cost inputs of the process to the lowest level possible.
*To view tables and figures, please visit:
About Cyprium Metals Ltd
Cyprium Metals Limited (ASX:CYM) is poised to grow to a mid-tier mining business and manage a portfolio of Australian copper projects to deliver vital natural resources, strong shareholder returns and sustainable value for our stakeholders. We pursue this aim, in genuine partnerships with employees, customers, shareholders, local communities and other stakeholders, which is based on integrity, co-operation, transparency and mutual value creation.
Cyprium Metals Ltd